The cytochrome c model project is complete and is being written up in full papers at this time. The preliminary conclusions reported last year have held up and remain unchanged. Progress this year has been made in the area of cytochrome oxidase models and "Structural Models for the Heme a3/Copper Active Site of Cytochrome c Oxidase" C.A. Reed and J.T. Landrum, FEBS Letters 106(2), 265-267 (1979), summarizes our progress. The imidazolate bridged model (Fe-Im-Cu) has been rejected in favor of an oxo bridge and our goal for the coming year is to prepare synthetic compounds containing this linkage (Fe-O-Cu). We will also investigate methods of synthesizing and characterizing Fe(IV) porphyrins, particularly analogues of Compd II of peroxidases.